This application relates generally to vehicle control systems and more particularly to integrated vehicle control systems.
Various vehicle subsystems are known to operate in different configuration modes to suit different conditions, which are changing in a long-term basis. For example, automatic transmissions can be controlled in sport, winter, economy, and manual configuration modes in which the changes between gear ratios and other subsystem control parameters are modified to suit the prevailing conditions or the driver's preferences. Air suspensions are known with on-road and off-road configuration modes. Power steering systems can be operated in different configurations modes where the level of assistance varies.
Conventionally, operation of each vehicle subsystem is controlled by the driver based on preference and experience. As the number of controllable subsystems increases, the driver may face an increasing number of choices of which configuration modes to select for each subsystem. In addition to the merely increasing the number of choices available, this situation also increases the potential for unexpected system interactions as well. Unless the driver is very experienced, this situation, being complicated can result in unintended vehicle behaviors.
Moreover, optimal vehicle performance relies on the control coordination among different configuration modes of the individual subsystems. For instance, brake control, active front steering, and active rear steering can all affect a vehicle's yaw stability. Thus, control coordination is required among these subsystems. In addition, the driver's preference should also be taken into account.
It would be highly desirable to develop an integrated vehicle control strategy that automatically determines an appropriate setting for each vehicle subsystem, and manages control coordination among the different settings.